1. Field of the Invention
The present invention relates to a semiconductor device manufacturing method.
2. Description of the Related Art
Regarding solid-state image pickup devices as one type of semiconductor device, a solid-state image pickup device including an optical waveguide has recently been proposed to increase a quantity of light incident on a photoelectric conversion portion.
Japanese Patent Laid-Open No. 2010-103458 discloses a solid-state image pickup device including a waveguide that is made up of a clad layer having a low refractive index, and a core layer having a high refractive index and buried in a groove surrounded by the clad layer. As an exemplary method of manufacturing such a solid-state image pickup device, there is disclosed a method of forming the core layer over an entire surface of the clad layer in which an opening is formed corresponding to the photoelectric conversion portion.
However, the method of manufacturing the solid-state image pickup device, disclosed in Japanese Patent Laid-Open No. 2010-103458, has a difficulty in making the solid-state image pickup device flatter. This results in degradation of image quality. Further, in a semiconductor device other than the solid-state image pickup device, the device height is increased with a higher degree of integration, and a difficulty in reducing the device height in a manufacturing process may become a problem to be overcome.